Placenta-on-a-chip models what is "arguably the least understood organ in the human body"

The new device is able to accurately simulate the development of the placental barrier(Credit: University of Pennsylvania)

The organ-on-a-chip concept has been around for a while now, providing researchers with working, lab-based models of heart disease, the human gut, and more. Now, researchers from the University of Pennsylvania have created the first ever placenta-on-a-chip that can simulate the flow of nutrients between mother and fetus. The device accurately simulates the development of the organ, and could provide insights to help prevent preterm births.

The concept of an organ-on-a-chip is to provide scientists with a device that closely mimics the function of a living human organ, providing a means of studying and developing new treatments that's both safer and potentially more accurate than animal testing. The placenta is an ideal candidate for such a device, as we know comparatively little about it.

"The placenta is arguably the least understood organ in the human body," said University of Pennsylvania's Dan Huh. "And much remains to be learned about how transport between mother and fetus works at the tissue, cellular and molecular levels."

The reason for that lack of understanding is largely due to difficulties associated with studying actual placental tissue. Not only are samples difficult for researchers to come by, but the tissue only remains viable for study for a few hours following delivery.

The new device, which is constructed largely from clear silicone, is about the size of a flash drive. It contains two layers of human cells – trophoblast cells and endothelial cells - which are used to model the interface between a mother and growing fetus. Microfluidic channels are connected to each of the layers, allowing researchers to study how molecules are blocked by, or transported across the barrier.

Study lead Dan Huh has actually been working to create such a device for a while, being part of a 2015 National Institutes of Health (NIH) project to create a very similar system. The new, University of Pennsylvania-developed device improves on the earlier attempt, in that it's able to more accurately simulate the interaction between the layers of maternal and fetal cells during pregnancy.

More specifically, the new system is able to facilitate a process called "syncytialization", wherein the cells fuse together during development, and the barrier is able to replicate the thinning that occurs as pregnancy progresses. This accurate formation and development of placental tissue allows the system to provide an accurate simulation of the transport function of the actual placental barrier.

The researchers confirmed that the hardware works by studying glucose transfer rates across the lab-based barrier, comparing the readings to those observed in donated human placentae.

The chip could significantly improve our understanding of the organ, allowing researchers to study how the placental barrier deals with the transportation of nutrients, as well as with viruses, which can pose a serious risk to the health of the growing fetus. While the device is still fairly early on in development, the researchers believe that it could provide invaluable insights into the causes of preterm birth.

Full details of the research are published online in the journal Lab on a Chip.